Project ID: 2011IN313BTitle: Niche breadth variation with seasonal changes in local habitats: fish assemblages of the Wabash River Project type: ResearchStart date: 3/01/2011End date: 2/29/2012Congressional district: IN-006Focus categories: Ecology, Geomorphological Processes, HydrogeochemistryKeywords: Fish assemblages, geomorphology, hydrology, substratesPrincipal Investigator: Pyron, Mark (Ball State University)Federal funds: $ 13,000Non-Federal Matching Funds: $ 27,298Abstract: Understanding the species- and assemblage-habitat relationships of large river fishes has been historically limited by the large size and spatial complexity of river ecosystems. However, a Geographic Information System (GIS) database constructed with spatially explicit physical data as well as information on occurrences of individual taxa can provide ecologists with appropriate tools to detect habitat use patterns for species and assemblages in these ecosystems. This proposal describes a study to test hypotheses associated with environmental factors regulating river fish assemblages that have not been amenable with other analytical approaches. I apply a method for collecting and analyzing fish species data for a 30-km reach of the Wabash River to test the relationships between niche breadth, niche position, and species abundance. Niche breadth and niche position are calculated using environmental variables (bathymetry, riverbed sediment composition, woody debris presence, and flow velocity) assembled in a spatially explicit GIS framework. I will use three resolutions to determine at which scale niche breadth and position are correlated with population density, and how these relationships vary among two seasons.